Exploring Black Soldier Fly Frass asNovel Fertilizer for Improved Growth,Yield, and Nitrogen Use Efficiency ofMaize Under Field Conditions

Black soldierfly frass fertilizer (BSFFF) is increasingly gaining momentum worldwide asorganic fertilizer. However, research on its performance on crop production remains largelyunknown. Here, we evaluate the comparative performance of BSFFF and commercialorganic fertilizer (SAFI) on maize (H513) production. Both fertilizers were applied at the ratesof 0, 2.5, 5, and 7.5 t ha-1, and 0, 30, 60, and 100 kg nitrogen (N) ha-1. Mineral fertilizer (urea)was also applied at 0, 30, 60 and 100 kg N ha-1to establish the N fertilizer equivalence (NFE)of the organic fertilizers. Maize grown in plots treated with BSFFF had the tallest plants andhighest chlorophyll concentrations. Plots treated with 7.5 t ha-1of BSFFF had 14% highergrain yields than plots treated with a similar rate of SAFI. There was a 27% and 7% increasein grain yields in plots treated with 100 kg N ha-1of BSFFF compared to those treated withequivalent rates of SAFI and urea fertilizers, respectively. Application of BSFFF at 7.5 t ha-1significantly increased N uptake by up to 23% compared to the equivalent rate of SAFI.Likewise, application of BSFFF at 100 kg N ha-1increased maize N uptake by 76% and29% compared to SAFI and urea, respectively. Maize treated with BSFFF at 2.5 t ha-1and30 kg N ha-1had higher nitrogen recovery efficiencies compared to equivalent rates of SAFI.The agronomic N use efficiency (AEN) of maize treated with 2.5 t ha-1of BSFFF was 2.4times higher than the value achieved using an equivalent rate of SAFI. Also, the AENof maizegrown using 30 kg N ha-1was 27% and 116% higher than the values obtained usingequivalent rates of SAFI and urea fertilizers, respectively. The NFE of BSFFF (108%) was 2.5times higher than that of SAFI. Application rates of 2.5 t ha-1and 30 kg N ha-1of BSFFFwere found to be effective in improving maize yield, while double rates of SAFI were required.Ourfindings demonstrate that BSFFF is a promising and sustainable alternative tocommercial fertilizers for increased maize production.